Houses and Environmental Hazards

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Millions of houses are affected by hazardous substances and detrimental environmental conditions. These conditions range from elevated radon levels that can be corrected for a few thousand dollars to PCB and other hazardous chemical levels that are so high that the house is not habitable.

In 1980, Congress passed the Comprehensive Environmental Response Compensation and Liability Act (CERCLA), one of a series of acts that gave extended powers to the Environmental Protection Agency (EPA) to clean up the environmental mess in the United States that had been accumulating for many years. Initial funding was provided by a special tax on the chemical and petroleum industries and a $1.6 billion Hazardous Waste Trust Fund (popularly known as the Superfund) was established.

Part of the work that the EPA does is to educate the public about the hazardous effects of being exposed to various substances and what can be done to reduce the public’s exposure and thereby reduce the risk of injury. The balance of this section explains what can be done to make a house safer to live in.


The following is a list of environmental problems that affect houses throughout the United States:

1. Unsafe drinking water.

2. Unsafe liquid-waste disposal.

3. Soil contaminants on-site or nearby.

4. Asbestos.

5. Radon.

6. Underground storage tanks (USTs).

7. Urea-formaldehyde foam insulation (UFFI).

8. Lead paint.

9. Air pollution indoors or outdoors.

10. Flooding—wetlands or floodplains.

11. Radiation and electromagnetic radiation.

12. Light and noise.

13. Geological hazards.


Every house needs an adequate supply of safe drinking water. The inconvenience and expense of having to use bottled water will negatively affect the value of a house. In some jurisdictions, a house without an adequate safe supply of drinking water may be declared uninhabitable. The need for adequate safe drinking water was recognized by Congress in 1974, when it passed the Safe Drinking Water Act (SDWA). This law and its 1986 amendment empower the EPA to protect the public from contaminated drinking water.

One of the causes of contaminated drinking water is bacteria. In the United States, the most common bacterium causes acute gastrointestinal illness (AGI), also called gastroenteritis; the next most common bacterium causes giardiasis. Other diseases transmitted by drinking water are shigellosis, campylobacteriosis and salmonellosis. Fortunately, bacteria-caused cholera and typhoid are rare in this country.

Lead is one of the most dangerous substances humans can ingest. Children are especially susceptible to its harmful effects, which may include serious damage to the brain, kidneys, nervous system and red blood cells. Infants are the highest risks because they can be harmed by even the small amount of lead that may get into their formula or in their first drinking water. If there is any possibility that the water is not lead-free, bottled water should be used for infants.

Lead can get into water in many ways. The most common ways are from the well and the water pipe connecting the municipal water supply to the house and from the pipes and fixtures within the house. Drinking water also can be contaminated by radon, PCBs, dioxins and many other hazardous chemicals.

Public Water Systems

More than 90 percent of the people in the United States get their drinking water from public water systems. Most of this water is supplied by large regulated water systems that supply ample safe drinking water. These systems maintain the safety of their water starting at the sources, which are surface water and underground wells. They filter the water when necessary and add chlorine and other chemicals as needed to purify it. Chlorine has an unpleasant taste and smell and may have some other undesirable side effects. Despite this, chlorine still is widely used because most public-health officials believe the benefits of treating water with chlorine far outweigh its known risks and unpleasant taste and odor.

The record of the large public water systems of supplying safe drinking water is extremely good. Unfortunately, the same is not true for the small water companies that serve about 25 million Americans.

Private Water Supplies and Wells

Millions of Americans still receive their drinking water from private wells and other private water supplies. The possibility that water from these sources is unsafe is substantially higher than when water is supplied by a public water company.

Testing Water

The only way to determine if a domestic water supply is safe is to have it tested. The local health agencies of many communities provide water tests at reasonable costs. Many commercial laboratories also provide water tests. When drawing samples, the instructions provided by the laboratory must be followed carefully. When the results of the water test indicate there are problems, immediate steps should be taken to correct them. Local health authorities are excellent sources of advice on how to correct the problems.


Liquid waste is the waste from sinks, baths, showers, washing machines, dishwashers, toilets, etc. It normally is disposed of by a municipal sewer system or in septic tanks or cesspools. Unfortunately, in some houses, it flows untreated into the soil or into nearby bodies of water.


By far the most satisfactory way to dispose of liquid waste is by a municipal sewer system. The waste flows by sewer pipes to treatment plants and then is discharged, usually into natural waterways.

Septic Systems

How septic systems work is described in Section 8. Unfortunately, health experts estimate that 50 percent of the septic systems in use seriously mal function at least once a year. When the malfunction occurs, untreated sewage flows into soil, often contaminating sources of drinking water.

Homeowners should have their septic systems professionally checked several times a year (more often when previous inspections indicate problems and unsatisfactory operation.) Pumping out, replacing the leaching fields and other steps may be required to keep the system in good working order.


Cesspools are primitive forms of waste disposal that often malfunction. They should be replaced with septic systems or municipal sewers when ever possible.


The most common soil contaminant is liquid waste, which was previously discussed in this section. In addition to getting into the drinking water, these contaminants can be directly harmful to humans.

Toxic chemicals that get into the soil are spread through runoff and leaching. Runoff occurs when water sweeps contaminants on the ground into wells, rivers, lakes or adjacent land. Leaching is the process by which contaminants are flushed by water through permeable soil.

Though not new, the true danger of the hazardous-waste problem was extensively reported to the American people in 1978 when they learned about the Love Canal in Niagara Falls, New York. At this site 25 years earlier, large amounts of toxic wastes were buried. Residents experienced skin rashes, blisters and a large variety of medical problems including a cancer rate many times higher than normal. The problem was so severe that many of the houses in the area had to be evacuated.

Many similar stories were reported and the public became aroused. As a result, Congress passed CERCLA in 1980, as previously mentioned. This Superfund act gave the EPA the authority to require anyone, including former owners and tenants, to pay for cleaning up his or her contaminated property. Often the cost of the cleanup is greater than the value of the property.

A homeowner unlucky enough to discover that his or her home is seriously contaminated may face massive cleanup costs and, in addition, find that his or her property is substantially reduced in value.

Nearby Hazardous-Waste Sites

Houses that are on or near sites that historically have been used as dumps for toxic materials are in danger of being contaminated with these materials, which can be carried above or below ground by water to the house Sites.

Each state maintains, together with the EPA, a list of known or suspected hazardous-waste sites. Nationally, more than 35,000 sites now appear on these lists. The worst of these sites are listed on the EPA’S National Properties List (NPL). The NPL sites are fenced off and marked with warning signs so their locations are well known.

Soil Contamination Identification

The only way to be certain that a site is free of soil contamination is to have it tested by a qualified soil-testing professional. Unfortunately, this is an expensive procedure.

Following are nine things a homeowner can look for that may indicate a site is contaminated:

1. Observed or known NPL of CERCLA-listed hazardous-waste sites or any other waste sites on or near the subject property.

2. Nearby observed or known sources of present or past soil contamination.

3. Information disclosed about problems with soil contamination by owners, occupants and others knowledgeable about the property.

4. Ground areas with stains or excessively stressed vegetation.

5. Sizable areas of debris, trash or junk on the property.

6. Seeping or unusual standing fluids.

7. Unusual odors.

8. Dead wildlife.

9. The property now or in the past was used for commercial, industrial or agricultural purposes.


Asbestos is a natural mineral that is mined and made into a variety of building products and fireproofing materials. Studies of workers who were exposed to large amounts of asbestos indicate that it can cause cancer in humans. No direct conclusive evidence exists that the amount of asbestos found in most homes is sufficient to be harmful.

Asbestos is believed to become dangerous when it is disturbed and its small fibers become airborne (friable). Home renovations, floor sandings and any attempt to remove asbestos material increase its chances of be coming friable.

Since 1979, the use of asbestos in building materials has been reduced substantially.

Asbestos has been used in the manufacture of thousands of different materials. The identification of many of these materials can be accomplished only by a trained expert. This checklist does not identify all the potential locations of asbestos on a property and is intended only to point out some of the common places where asbestos is found:

1. Ceilings: Any ceiling tile or other ceiling material has a high probability of containing asbestos. Sprayed-on ceiling coatings also have a high probability of containing asbestos, as do ceilings that have a lumpy cottage-cheese appearance. Any commercial, industrial or institutional building ceiling installed before 1979 has a very high probability of containing asbestos and some residential ceilings contain asbestos. Ceilings built after 1979, however, also may contain asbestos.

2. Electric appliances: Almost all electric and gas appliances contain asbestos.

3. Floor covering: Many floor-covering materials contain asbestos.

These include but are not limited to linoleum, floor tiles and carpet backings. When floors are sanded, scraped or ripped up as part of a renovation, the asbestos becomes friable.

4. Fireproofing: Any material that was used as fireproofing has a very high probability of containing asbestos.

5. Heating ducts and pipes: Asbestos was commonly used to line the inside and outside of heating ducts and pipes in residences as well as other types of properties. It also was used to make some heating ducts and pipes.

6. Heating systems: Asbestos was commonly used to make all types of heating systems. Older heating systems almost always contain asbestos and even new heating systems may contain asbestos.

7. Hot-water pipes: Asbestos was commonly used in materials that were wrapped around hot-water pipes.

8. Insulation: Many insulation materials contain asbestos.

9. Siding: Many siding materials contain asbestos.

10. Roofing: Many roofing materials contain asbestos.

11. Wall covering: Many wall-covering materials contain asbestos.

12. Wire: Many types of wire contain asbestos.


Radon-222 is a radioactive gas. Humans cannot see, smell or taste it, but this gas turns up almost everywhere.

Radon occurs naturally in rocks and soil. Radon atoms are uranium’s direct descendants. When atoms of Uranium-238 decay, they produce several generations of other radioactive elements. The fifth generation is radium, which, in turn, decays into radon.

Radon occurs naturally almost everywhere. Current estimates are that the average U.S. home contains about 1.5 picocuries of radon. In “hot spots,” home readings soar over 2,000 picocuries per liter (pCi/l). Radon readings tend to range highest in areas with high concentrations of uranium-bearing rocks such as granite.

The EPA now estimates that approximately 20,000 Americans die each year because of radon-induced lung cancer. Thus, radon causes more deaths than any other environmental pollutant under the EPA’s vast jurisdiction.

The cancer-causing effects of radon in a house are similar to those of cigarette smoking. When people are exposed to both, the harmful effects are multiplied.

Currently, the EPA has set the safe radon level at 4 pCi/l or 0.02 WL (the other method by which radon levels are measured). Exposure to 10 pCi/l to 20 pCi/l is comparable to smoking one pack of cigarettes a day, 20 pCi/i to 40 pCi/l is comparable to smoking two packs of cigarettes daily and 100 pCi/l to 20 pCi/l is comparable to smoking four packs of cigarettes daily. Every house should be tested for radon.

EPA surveys show that there are houses with high radon levels in every county in the United States. No house, therefore, can be presumed free of excess radon based on its location.

Fortunately, radon tests are easy to make and are inexpensive. They are not as accurate as the more sophisticated tests made by professional radon inspectors, but they will alert a homeowner to a potential radon problem and indicate whether further testing is necessary.

The fastest way to find out if a radon problem exists is to place a short-term testing device in the house for a few days to several months. Short-term tests, however, should be used only in the lowest living area of the house, with doors and windows closed, during the cooler months of the year. This process reduces the chance of measuring the house when radon levels are lower than usual. Charcoal test kits and electretion detectors are the most common short-term testing devices.

The following sections are quoted from EPA publications.

Deciding Whether to Fix Your Home

Because no level of radon is considered absolutely “safe,” a person should try to reduce radon levels in his or her home as much as is possible and practical. The average radon level in homes is about 1.5 pCi/l. A per son should definitely take action to reduce radon if the average annual level is higher than 4 pCi/l.

Things to Consider

In addition to testing radon levels, a homeowner concerned about radon exposures, while considering and taking specific actions, should ask several questions to determine radon risk:

• Does anyone in the house smoke?

• Are there children in the family?

• Do people spend unusually high amounts of time in the home, per haps because of individual illnesses, age, occupation or personal preference?

• Does anyone sleep in the basement, where radon levels are higher than on the floors?

The more affirmative answers a homeowner has to these questions, the sooner he or she should act to reduce the radon levels of the house.

Here are some actions that homeowners can take to reduce radon risks to themselves and their families:

• If possible, spend less time in areas where radon levels are highest, such as the basement.

• Stop smoking and discourage smoking in the home. Smoking may in crease the risk of exposure to radon, in addition to increasing the overall chances of getting lung cancer.

• As often as practical, open windows throughout the house and turn on fans to increase the air flow into and through the house, especially in the basement.

Long-Term Actions to Reduce Radon Exposure

For homes with higher radon concentrations, radon officials recommend, along with the above, more thorough actions to reduce those levels—actions that either reduce the rate at which radon enters the house or force the radon out of the house once it has entered.

Reducing the rate of radon entering the house can be accomplished either by blocking off or sealing the places in which it enters, or by reversing the direction of the flow of these pathways so the indoor air and radon are pushed out of, rather than brought into, the house. The best way to force radon out of the house is to increase ventilation.

A contractor who specializes in ridding homes of radon should be hired for the more complex remedies. These contractors in general are not the same firms that produce radon detectors. The EPA regional offices, state radon offices, Better Business Bureaus and local consumer-affairs departments should have lists of radon contractors.

Long-term methods to reduce radon levels include:

Sub-slab suction by installing pipes and fans to pull radon from under the slab foundation generally is considered the most effective radon- reduction technique. The same approach can be taken with drains and/or block walls. A trained professional should install the system.

Sealing major radon sources and entry points involves covering ex posed earth in basements, storage areas, drains and crawl spaces with impermeable materials, such as plastic or sheet metal, and sealing cracks and openings with mortar or urethane foam. This step usually is considered most effective when taken in combination with other radon- reduction efforts. Advice on identifying areas to seal should come from an experienced professional, who may have to do some of the work.

Forced cross-ventilating is accomplished by using fans on both sides of the house.

Heat-recovery ventilating is suitable in homes that need heating for several months of the year. A heat-recovery ventilator or “air-to-air heat exchanger” has a pair of fans to blow stale air out of the house and draw in fresh air. The fans also reclaim some of the heat the furnace generates while maintaining the adequate ventilation needed to reduce the home’s radon. Installation and annual operating costs will vary widely through out the country.

Adjusting air pressure within the house can be accomplished by pro viding air from outside to appliances that would otherwise use air in the house for combustion. By providing appliances such as the furnace, fire place and clothes dryer with external sources of air, the air pressure inside the house is increased, reducing the amount of radon drawn up into the house. This work must be done by an experienced professional, and the costs will vary according to the difficulty of venting each appliance.


The EPA has estimated that 25 percent of all USTs currently are leaking. These are known as Leaking Underground Storage Tanks (LUSTs) and fluids that leak from them not only contaminate the property where they are located but also affect nearby properties. When the leaking material gets into the ground water, it can travel substantial distances.

By far, the most common products stored in USTs are petroleum products. USTs also are used by chemical, pesticide, automotive, leather- tanning, metal-forming and plating, recycling and wood-treatment companies, wineries, breweries, food processors, paper and pulp mills, salvage operations, medical laboratories, paint manufacturers and a wide variety of other processing operations.

It is impossible to determine just from observation whether there are or have been USTs on or near the subject property. This can be deter mined only by testing for USTs by a qualified UST and/or environmental inspector.

Apparent Indications of Possible USTs

The purpose of this checklist is to help the appraiser identify apparent USTs. The observation of or knowledge about one or more of these items does not necessarily indicate that a UST exists. Also a UST may be located on or near the subject property without any of these items being apparent. Furthermore, the existence of USTs may be indicated by apparent items that do not appear on this list. Nobody should depend on the observation and knowledge of these items to determine if any USTs exist on or near the subject property. This can be determined only by inspections and tests made by a qualified UST and/or environmental inspector.

Apparent indications of possible USTs include:

I. An indication by an owner, occupant or someone else knowledge able about the property that he or she believes there is or was a UST on or near the subject property.

2. Nearby observed or known sources of present or past soil contamination.

3. Information disclosed about problems with the soil contamination by owners, occupants and others knowledgeable about the property.

4. Ground areas observed with stains or excessively stressed vegetation.

5. Seeping or unusual standing fluids.

6. Unusual odors.

7. The property now or in the past was used for commercial, industrial, institutional or agricultural purposes.

8. The site now or in the past is known to have contained USTs.


Formaldehyde is a colorless, gaseous chemical compound. It has a pun gent odor that may not be detectable when very small quantities are present.

Formaldehyde can cause cancer in animals and therefore may cause cancer in humans. In some people, it triggers asthma attacks or causes skin rashes, watery and burning eyes and burning sensations in the eyes, nose and throat.

Urea-formaldehyde foam insulation (UFFI) first was used as a building material in 1970. It is a thermal insulation material that is pumped into the spaces between the walls of a building where it hardens to form a solid layer of insulation. Because of its shaving cream-like quality, which enables UFFI to fill hard-to-reach places, it was a popular substance used in insulating homes. This type of insulation has been installed in approximately half a million homes in the United States.

In 1982, the Consumer Product Safety Commission (CPSC) banned the future sale and installation of UFFI, after determining that it presented an unreasonable health hazard to those exposed to it because of the formaldehyde gas released from the UFFI product in building interiors. The severity of these problems varies from short-term discomfort to serious health impairment. The CPSC was not able to identify a level of formaldehyde exposure at which the general population could be assured that no adverse effects would occur.

The CPSC ban subsequently was challenged in the courts and the U.S. Fifth Circuit Court of Appeals overturned the CPSC’s ban, finding that the CPSC did not have sufficient evidence with which to issue its ban. The court, however, specifically declined to hold that UFFI was a harmless substance. The CPSC ban on UFFI installation was lifted, al though public opinion resulting from this controversy dramatically reduced the popularity of UFFI as an insulating material.

The debate regarding the potential health effects resulting from living in UFFI-insulated homes continues. A March 3, 1986, report by the National Cancer Institute (NCI) added fuel to this debate when the institute found little evidence that formaldehyde causes cancer among the more than 1.3 million workers who are regularly exposed to it in more than 50,000 factories. Many scientists feel that three to four years after UFFI is installed, formaldehyde emissions become minimal and pose little human health risk.

Where UFFI Is Found

Large amounts of formaldehyde are contained in certain types of foam insulating materials that were widely used for home insulation. In the United States, this product no longer is used, but millions of homes still contain large amounts of it. Many experts feel that because the toxic effect of UFFI decreases as it ages and because most of it is more than six years old, the dangers from this product are diminishing. This type of insulation, however, reacts to high temperatures and still is a hazard when found in attics because excessive heat still may cause it to emit formaldehyde fumes.

Also, UFFI can be reactivated when it becomes wet, thus presenting a problem when it is located in areas that become wet or damp.

Whenever alterations or other remodeling is contemplated, the effect of disturbing products containing UFFI must be considered.

Other products containing formaldehyde are adhesives, especially those used to bond pressed-wood and plywood building materials. Formaldehyde also is found in furniture glue, certain foam upholstery / cushion materials, some paint preservatives, coating products, carpet backing and permanent-press fabrics.

Especially large amounts of formaldehyde materials were used prior to 1985 in the construction of prefabricated and mobile homes. Federal regulations have limited their use since 1985.

All use of formaldehyde-containing materials, however, has not been stopped. It still is widely used in furniture manufacture and in selected building materials.

Formaldehyde is a by-product of combustion, produced by smoking cigarettes or using fireplaces, stoves, furnaces, or kerosene and gas heaters. Poor ventilation increases the amount of formaldehyde left in the home. Fortunately, the older a product gets, the less the product emits formaldehyde gas.

Identification and Testing

The easiest way to test for the presence of UFFI is to check in any area where outer walls might be exposed. It looks like ordinary shaving cream and when dry, is either tan or white and fluffy like Styrofoam.

Formaldehyde gas is difficult to detect without testing, for it has no odor except when present in high concentrations. The best way to deter mine formaldehyde-gas emission is to collect a foam sample and conduct a lab test.

These tests usually cost about $50 and take over an hour to collect the necessary material. In some areas, tests are provided by local or state health departments. A full on-site air inspection is more costly but can yield more accurate results. Testing kits also are available for homeowners to test or monitor their own formaldehyde levels.

According to advisory standards established by the state of Wisconsin, formaldehyde concentration above 0.4 ppm is considered a significant potential health risk. Even concentrations as low as 0.11 ppm may result in mild adverse reactions among some individuals.

Unfortunately, many difficulties are associated with formaldehyde testing. Variable conditions such as temperature, humidity and ventilation can affect test results.

In addition, there are many other sources of potential formaldehyde emissions besides UFFI such as carpeting, toothpaste, cosmetics, some paints and plywood. Any testing of formaldehyde-gas concentrations stemming from UFFI should take these considerations into account.

Abating UFFI

The complexity of the abatement procedure depends on what is the source of the formaldehyde gas.

If the gas comes from an identified piece of furniture—drapes, car pets, etc.,—all that is required is the removal of the furnishing emitting the formaldehyde gas. When the gas comes from building parts that are costly to remove and replace, then increased ventilation is a possible solution to the problem.

Another possible solution is to coat the material emitting the gas. The most common materials used as coatings are polyurethane-based paints or varnishes. Such a solution, however, is not always permanent.


The harmful effects of lead, especially on children, are described in the “Safe Drinking Water” section of this section.

Lead was a common material used in paints made prior to World War II. Between 1940 and 1960, the amount of paint made with lead was decreased and only about one-third of the houses built during that period contain lead paint. Since then, the use of lead house paint has been significantly reduced. The biggest lead-paint problems exist in low-income public housing and in older homes that are being renovated.

Harmful amounts of lead can get into the air from lead paint when it is scraped, sanded or heated with an open flame during a paint-removal process.

Once the lead gets into the air, it is inhaled into the body. Ingesting lead-paint chips is especially hazardous for children. As lead settles on the floor, it is reintroduced into the air each time the carpets or rugs are swept or vacuumed. Particles of lead are so fine that they can pass right through the vacuum cleaner filter and into the house air. They usually cannot be seen by the human eye.


A surface that has lead is an immediate or future hazard when the surface is chewable or damaged, cracked, loosened or chipped. Any paint that was applied prior to 1980 may contain lead. Paints manufactured after 1977 contain less than 1 percent lead.

Paint applied before 1980 that is peeling from floors, walls, windows and sills, door and frames, stair railings and banisters, woodwork molding and baseboards, porches, pipes and fixtures, ceilings, fences and exterior surfaces of houses and garages should be tested to determine whether the amount of lead exceeds .06 percent. Lead in paint can be tested in one of two ways. Paint chips can be collected and analyzed either on the site or in a laboratory. Portable X-ray fluorescence (PXF) analyzers also can be used to determine lead content directly at the site. Test results of 0.7 mg/cm or more indicate excessive lead content.


Abatement requires removal or placing a solid fireproof barrier such as wallboard, hardboard or plywood over the surface that contains the lead. Lead-based paint should be disposed of according to local and federal lead-disposal requirements.

Unfortunately, studies are showing that sanding and burning off the lead paint may be as obsolete and as hazardous a procedure as ripping out asbestos without personal protective equipment. Painting over lead- containing paint with lead-free paint also is not sufficient.


Recent surveys indicate that the pollutant levels within the average U.S. home are higher than those in the air outside the home. These surveys also suggest that the level of pollutants often is potentially harmful to the occupants.

Most people spend approximately 90 percent of their time indoors. The quality of the indoor air they breath, therefore, has a potentially significant effect on their health. Ironically, people who are most exposed to indoor air pollutants are, because of their older age and poorer health, the people who are most susceptible to the adverse effects of indoor air pollutants.

Outdoor air enters and leaves a building in three ways:

1. Infiltration: Where the air flows through construction joints and cracks around windows and doors or in the foundation, or from crawl spaces or other areas under the building.

2. Natural ventilation: Where air enters through open windows and doors.

3. Mechanical ventilation: Where a variety of mechanical devices ranging from small window fans to complex computer-controlled heating and air-conditioning systems are used.

The rate at which outside air replaces indoor air is called the air-exchange rate. When there is little infiltration, natural ventilation or mechanical ventilation, the air-exchange rate is low and the amount of indoor air pollution can increase.

The harmful effects of indoor air pollutants fall into two categories: those that are experienced immediately after exposure and those that do not show up for a long period of time after exposure to the pollutants. Some of the immediate symptoms that people experience after either a single or repeated exposure to air pollutants are irritation of the eyes, nose or throat, headaches, dizziness, fatigue or nausea. These symptoms are often of short duration and may be alleviated by eliminating exposure to the source of the pollutant. The likelihood of developing any of these symptoms varies from person to person and often is related to age and health.

Evidence exists that people can become sensitized to biological pollutants after repeated exposure. This also appears to be true for exposure to chemical pollutants. More serious health problems connected with expo sure to indoor air pollutants show up only after repeated exposure over a long period of time. These long-term effects include emphysema and other respiratory diseases, heart disease and cancer.

There is general agreement that indoor air pollutants are responsible for some of these medical conditions. There is considerable uncertainty, however, about what concentrations or periods of exposure are necessary to produce specific health risks and adverse effects. The two ways to reduce air pollution in a building are to increase ventilation or to remove the sources of pollution.

The most common way to identify the presence of indoor air pollutants is by the immediate effect that they have on people who become exposed to them. Symptoms often appear after a person moves into a new home or workplace, after remodeling, after refurnishing or after a building has been treated with pesticides.

People who think they have symptoms that may be caused by air pollutants should consult their doctor. They also may discuss the problem with their local health department. If a building contains any sources that may cause indoor air pollution, the atmosphere will contain air pollutants. It is possible (but quite expensive) to test for air pollutants. When the sources are controlled, the level of air pollution decreases.

Following is a summary of the major indoor air pollutants and the methods used to remove these sources of indoor air pollution.

1. Tobacco smoke is produced by smoking cigarettes, pipes and cigars. Stop people from smoking in the building. Nonsmokers’ exposure to environmental tobacco smoke is called passive smoking, second hand smoking or involuntary smoking.

2. Biological contaminants include bacteria, mold and mildew, viruses, animal dander, cat saliva, mites, cockroaches and pollen. Be careful when using cool-mist or ultrasonic humidifiers. Keep basements dry by using a dehumidifier. Clean and disinfect basement floor drains regularly. These can become the breeding ground for biological contaminants. They should be cleaned frequently and filled with clean water daily.

Thoroughly dry and clean water-damaged carpets and other building materials as soon as possible after they have become wet and damaged. Keep the building clean. Dust mites, pollens, animal dander and other allergy-causing agents can be reduced although not completely eliminated by regular thorough cleaning. Unfortunately, vacuuming can stir up some airborne biological contaminants. People who are allergic to these pollutants should avoid vacuuming and should leave the building when a vacuum cleaner is being used.

3. Carbon monoxide is a gas produced by combustion from unvented kerosene and gas heaters, leaking chimneys and furnaces, down- drafting from woodstoves and fireplaces, gas stoves, automobile exhaust from attached garages and tobacco smoke. Take special precautions when operating fuel-burning unvented space heaters. Follow the manufacturer’s instructions, use the appropriate fuel and keep the heater properly adjusted. A persistent yellow-tipped flame generally is an indicator of maladjustment and increased pollutant emission. When a space heater is in use, open a door from the room where the heater is located and open a window slightly. Install and use exhaust fans over cooking stoves and ranges and keep the burners properly adjusted. Never use a gas stove to heat a home. Be sure the flue is fully opened when using a fireplace (especially a gas fireplace). Keep woodstove emission to a minimum by using stoves that are certified to meet EPA standards. Make sure doors on old stoves are tight-fitting. Use only aged or cured (dried) wood. Do not use chemically treated wood.

Have central air-handling systems that include furnaces, flues and chimneys inspected annually. Repair any cracks or other damaged parts and change furnace filters monthly.

4. Nitrogen dioxide is a gas produced by unvented gas stoves and heaters and also from tobacco smoke. Use the same procedures as for carbon monoxide.

5. Respirable particles, small particles that float in the air, are produced by fireplaces, woodstoves, kerosene heaters and tobacco smoke. Use the same procedures as for tobacco smoke and carbon monoxide.

6. Organic gases are emitted from paint, paint strippers, solvents, wood preservatives, aerosol sprays, cleaners and disinfectants, moth-repellents, air fresheners, stored fuels, automotive products, hobby supplies and dry-cleaned clothing.

Products that emit organic gases should be used sparingly in well-vented areas following the manufacturer’s instructions. Store them in well-ventilated areas, safely out of the reach of children. Dispose of partially full containers of old or unneeded chemicals because they may leak. Keep exposure to tobacco smoke, stored fuels and paint supplies to a minimum for they contain benzene, a known human carcinogen.

Also, keep exposure to paint strippers, adhesive removers, aerosol spray paints and pesticide spray “bombs” to a minimum. They contain methylene chloride and other harmful chemicals. In addition, keep exposure to newly dry-cleaned clothes to a mini mum for they are cleaned with perchloroethylene, a suspected carcinogen.

7. Radon—for more information, see the “Radon” section of this section.

8. Formaldehyde—for more information, see the “Urea Formaldehyde Foam Insulation (UFFI)” section of this section.

9. Lead—for more information, see the “Drinking Water” and “Lead Paint” sections of this section.

10. Asbestos—for more information, see the “Asbestos” section of this section.

11. Pesticides—for more information, see the “Pesticide” section of this section.


Outside air pollution ranges from things that smell bad such as low tide and salt marshes, piles of rotting garbage and many wastes from manufacturing operations to air pollutants such as carbon monoxide, which is both odorless and deadly.

Some areas of the country are known for their severe air-pollution conditions. One well-known example is the Los Angeles basin. Studies made by the American Lung Association demonstrate that in Los Angeles, there is a direct connection between air pollution and acute upper-respiratory infections, influenza, bronchitis and other lung diseases, allergic disorders and heart and vascular diseases. Another large study by the American Lung Association indicated a substantial rise in the number of children hospitalized for asthma and eczema as a result of air pollution.

Air pollutants occur either in the form of particulate matters or gases. Many air pollutants of both forms are harmful to humans. Some air pollutants, such as sulfur oxides, eat away at bridges, building facades and sculptures. Even crops can be damaged by polluted air.

According to the EPA pamphlet Buying an EPA-Certified Woodstove:

Residential woodstoves are one of the nation’s largest sources of particulate matter air pollution (smoke). Wood smoke also contains significant amounts of carbon monoxide, hydrocarbons and many other organic compounds. These pollutants are known to cause respiratory and cardiovascular illness and contribute to atmosphere visibility problems and property damage. The EPA regulation requires manufacturers to produce new stoves that emit less pollution. As consumers replace their old woodstoves with cleaner, more efficient, new stoves, the quality of the air will improve—particularly in residential neighborhoods where woodstoves are popular.

Another major air polluter is automobiles. The 1977 amendments to the Clean Air Act (CLA) made it illegal to tamper with a car’s emission- control system. According to the EPA pamphlet Do You Own a Car?:

“Motor vehicles contribute more than one-half of the total man-made air pollution in this country. They emit nearly three-quarters of the total amount of the poisonous gas carbon monoxide. They also emit over one- third of the hydrocarbons and one-third of the oxides of nitrogen, two major causes of the unhealthy smog that hangs over a great many of our cities.”

The EPA pamphlet, A Cause for Alarm—Acid Precipitation in the Northeast, provides the following information about acid rain: “When airborne pollutants are transported through the atmosphere, some of the pollutants (such as sulfur dioxide and nitrogen dioxide) combine with water vapor to form acids. These air pollutants are literally washed out of the air by rain, snow and fog. Such precipitations are abnormally acidic thus the term ‘atmospheric precipitation,’ which is part of a more general process called ‘atmospheric disposition,’ during which other pollutants, such as heavy metals and toxic organics fall to earth, in both wet and dry weather.”

According to this same EPA pamphlet, the Northeast has the most problems caused by acid rain: “Prevailing wind patterns subject the Northeast to transported air pollutants year round. Granitic bedrock geology and related soils leave large sections of the Northeast with little natural defense against acid precipitation. Lakes, streams, and drinking water supplies naturally low in alkalinity have little ability to neutralize the acid and buffer its effects.”


Wetlands are lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface. Historically, wet lands have been considered as wastelands of little value to society and have been subject to dumping, filling and draining, with little thought given to the consequences caused by these activities. Only relatively recently has the role of wetlands become more fully understood in maintaining and improving environmental quality.

The ecological value of wetlands has been increasingly recognized and studied in recent years. Many diverse groups have lobbied with Congress to halt wetlands destruction since the growing realization of the strategic value of these resources. During the past two decades, much protective legislation restricting wetlands development and use has been is sued on federal, state and local levels.

Marshes are typified by an absence of trees and shrubs. They develop in low-lying areas that have high water tables. The dominant vegetation in marshes is soft-stemmed plants such as cattails, spatterdock and pickerel-weed.

A salt marsh looks like a sea of grass interlaced with tidal creeks that link life in the salt marsh to the sea. More than three and one-half million acres of salt marshes are scattered along the U.S. coast. They are most extensive between southern Massachusetts and northern Florida, but they also are abundant along the Gulf of Mexico and the coast of Alaska. They even can be found in isolated areas along the Pacific Coast.

Mullet, flounder, bluefish and menhaden depend on salt marshes and the adjacent estuaries for nursery and spawning grounds, as do shrimp, crabs, oysters and clams. Geese, ducks and other waterfowl mi grate to or live year-round in the marshes.

Swamps also developed in low-lying areas but, unlike marshes, are characterized by woody vegetation. Soft-stemmed plans such as the tussock sedge form a bottom layer to the swamp.

Freshwater swamps generally are thought of as being either forested or shrub swamps. One major type of forested swamp is the bottomland hardwood swamp that is found mostly in the Southeast. Some, such as the Okefenokee swamp in Georgia, are spread out over hundreds of square miles.

In bottomland hardwood swamps, bald cypress, tupelos, various oaks and other hardwood trees provide food and shelter for deer, wildcat, cougar, fox, raccoon, beaver and muskrat. Quail, dove and duck nest here and rear their young. Snakes, turtles, frogs and other reptiles abound.

Shrub swamps are characterized by scrubby, low-growing vegetation, such as water willow, pussy willow and leather-leaf. Snakes and other water-loving reptiles are common, as are a great variety of water birds, quail and songbirds. Frequently, fox, deer and raccoon also are seen in these swamps. Shrub swamps form in upland depressions and along rivers and slowly moving streams. In northern states, shrub swamps are commonly called heaths and in the Southeast they are called pocosins.

A special kind of swamp, the mangrove, is dominated by salt-tolerant trees. Approximately 523,000 acres of mangrove swamps are located in southern Florida, but some small ones can be found in coastal Louisiana and Texas. One type of salt-tolerant tree that dominates these swamps is the red mangrove. It grows impenetrable except by flat-bottomed boat. Mangrove swamps are nurseries for shrimp, sea trout, pompano, tarpon and other fish.

Bogs have formed in glacial kettle-holds and many have neither exit or entrance streams. Water stagnates in these depressions, forming an acidic environment where only certain kinds of vegetation will grow. Probably the most characteristic plant in a bog is sphagnum or peat moss. The moss forms mats along the surface with new layers growing on top of the old. On occasion, the depth of peat accumulation can exceed 20 feet.

Bogs are freshwater wetlands that usually contain a buildup of peat, which forms as plants die and fall into the water. Moss also grows in the water of some bogs, forming a thick carpet on which black spruce and other trees eventually grow.

Bogs are located mainly in the northeastern and north central United States. They usually form in poorly drained areas, typically in depressions caused by glaciers. In some bogs, the peat can be more than 40 feet thick. Many bogs support unusual plants such as pitcher plants and the sundew. Other common plants in bogs are myrtle, blueberry and tamarack.

Floodplains are lowland areas naturally found along watercourses. The vegetation cover in flood plains varies. Swamps and marshes usually are found dispersed on larger floodplains. Willows often grow along a river’s edge with cottonwoods and silver maples in a zone behind it.

Floodplains are subject to periodic flooding, usually during the fall and spring when seasonal precipitation is the highest. Engineers speak theoretically of a 10-year, 50-year and 500-year flood, with the severity of flooding increasing with the lowered frequency. Sites located within the 100-year flood zone should not be filled in or built on. Arbitrary filling or construction can lead to costly flood damage to structures built within the floodplain as well as aggravating flooding problems elsewhere within a river’s reach. Floodplains also make very fertile farmlands that have produced, since colonial times, crops such as corn, pumpkins, squash, beans, peas and tobacco.

The ecology of the coastal wetlands—those that lie along the coasts of the United States—is strongly affected by the adjoining seas. The salt content of the water and the rise and fall of the tides influence the types of plants that grow in the wetlands and the creatures that live among the roots and stalks of the plants.

A special value of coastal wetlands is their ability to soften the force of hurricanes and protect people and their homes from winter storms. Both environmentally and economically, wetlands may do a better job of damage control than man-made seawalls.

On the other hand, the presence of people and buildings often dam ages the wetlands. By 1990, it is estimated that 75 percent of the U.S. population will be living within 50 miles of the coastline. More people will mean more houses, more roads, more stores and more marinas—often at the expense of wetlands. Also, as people create more waste, they cause serious pollution problems for wetland areas.

Wetland Regulations

Activities within wetland and watercourse boundaries are heavily regulated. These regulations ensure an orderly and fair process to balance the need for the economic growth and the use of the land with the need to protect the land’s environment and ecology.

Wetland regulation occurs under a variety of federal laws in addition to the Clean Water Act. These regulations include the Coastal Zone Management Act (16 USC 1451-1464); Esturaine Areas (16 USC 1221-1226); Water Bank Program for Wetlands Preservation (16 USC 1301-1311); Rural Environmental Conservation Program (16 USC i501-l510) Migratory Bird Conservation Act (16 USC 715); Rivers and Harbors Act of 1899 (33 USC 401-466); Fish and Wildlife Coordination Act (16 USC 66 1-668); and Watershed Protection and Flood Prevention Act (16 USC 1001-1009).

There also are Executive Orders on Wetlands Protection and Flood plain Management. Permits are subject to the provisions of the National Environmental Policy Act (NEPA), which may require environmental assessments and environmental-impact studies.

Twenty-nine states have programs that pertain to coastal wetlands and inland wetlands. States that have programs in both areas include:

Alaska, Connecticut, Florida, Georgia, Hawaii, Indiana, Louisiana, Maine, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Washington, Wisconsin and West Virginia. Wetland-acquisition pro grams are conducted by all states except Alaska, Arizona, Hawaii, Kansas, Montana, Nevada, North Dakota, Oklahoma, Utah and Wyoming.

Failure to determine the presence of wetlands on a subject site and whether proposed activities will require a Section 404 permit, as well as compliance with any state and local regulations, can have serious and ex pensive consequences. In some instances, government agencies have required that existing structures be removed and that the land be returned to its natural state. Wetland legislation can drastically affect the highest and best use of real estate containing or bordering on wetlands and can significantly alter a property’s value.


Background Radiation

Radiation is caused by radioactive materials that release radioactive particles. Radioactive materials are used in nuclear plants, manufacturing facilities, medical facilities, laboratories, power-generation plants, etc. Exposure to any type of excess radiation is unquestionably harmful to humans.

Electromagnetic Radiation

“Health issues that affect our living environment often become important to relocation professionals as home purchasers seek redress for real or perceived harm they have suffered due to characteristics in their homes.” This is the opening sentence from the article “Electromagnetic Radiation, A New Hazardous Substance Issue for Relocation?”, which appears in the November, 1990, issue of Mobility, the magazine of the Employee Relocation Council. The author, Ronald J. Passaro, president of Res-I-Tec, a home-inspection company, is one of the best-informed people in the country on the subject of home inspections.

This article points out that newspapers are carrying stories about the growing concern over the perceived hazards of high-voltage power lines, emissions from radio- and television-station transmitters, video display terminals (VDTs), microwave ovens and television sets and the dangers to health from all sources of electromagnetic radiation. Passaro also says that as long as a significant number of people think electromagnetic radiation is harmful, it may affect the value of any property that is exposed to what is perceived to be excess amounts.

Electromagnetic radiation is a natural phenomenon, generated in large amounts by the geomagnetic field of the earth. It also comes to the earth from the sun and the stars. Its strength varies from place to place depending on a wide variety of factors, some natural, such as the iron-ore content found in the soil, and some man-made, such as the iron and steel in buildings and bridges.

The unit of measurement for electromagnetic radiation is called a “gauss,” named after Carl Friedrich Gauss, a German mathematician.

There are three broad categories of electromagnetic radiation. High- frequency waves include those known as ultraviolet rays and X-rays. The September, 1990, Buzzworm Environmental Journal article, “The Healthy Office,” by Richard Freudenberger, reports “ Food and Drug Ad ministration has stated that ultraviolet radiation from fluorescent bulbs can boost the risk of nonmalignant tumors. Other sources go further and link fluorescent lights to a form of malignant cancer.”

Visible light, infrared light and microwaves are middle-frequency waves. Radio and television transmitters emit low-frequency waves. Extremely low-frequency waves (ELFs) are emitted from high-voltage power lines, all other types of wiring including household wiring and all electrical appliances.

There is very little proof that most electromagnetic radiation is harmful to humans. One exception is high-frequency X-ray radiation that, with excess exposure, is linked to cell destruction and some cancers. On the other hand, some scientists believe that all electromagnetic waves are harmful and that it is just a matter of time before this will be proven scientifically.

Screening Guidelines

Homeowners should try to determine if there is any X-ray equipment, radioactive material or other potential source of radiation on or near the subject property.

These sources of radiation may range from a few containers of radio active material found in a laboratory, safely stored in approved cabinets or lockers, and/or small X-ray machines that are safely shielded to large amounts of radioactive material and large X-ray equipment found in manufacturing facilities and medical facilities such as hospitals, nursing homes, medical and dental offices, research laboratories, etc.

Almost every property contains TV sets, computer terminals, wiring and many other items that produce electromagnetic radiation. Reductions of these items will reduce the potential amount of electromagnetic radiation.


Light shining onto a property and noise are sources of pollution. Light pollution ranges from the light from occasional headlights of passing automobiles to large amounts of light from sports complexes, shopping centers and malls, parking lots, etc. Often it is possible to screen a property from some of these objectionable sources of light.

Noise pollution also is caused by a variety of sources, the most common of which is automobile and truck traffic. Recently, the federal government instituted the construction of sound barriers on the interstate highways in an attempt to reduce the high level of noise created in some areas.

Other noise problems are more difficult to control. Some of these problems are the noise caused by trains, airplanes, sports complexes, nearby industries, etc. People who are concerned about high levels of noise should be careful to screen any property that they plan to buy or rent for potential noise sources. Sometimes it is possible to reduce noise levels by plantings and other barriers erected on the property.


Every parcel of real estate is an integral part of the surface of the earth that is constantly changing. These changes are evidenced by the erosion of the coastlines and farmlands, landslides, earthquakes and volcanic activity. They create geological hazards that threaten property and human life.

Other geographic hazards are not a result of this constant change but are caused primarily by the configuration of the earth, such as sheer precipices or areas prone to flooding or being covered by wetlands.

Before buying or renting a house, an attempt should be made to identify any potential exposure from a geological hazard. When one or more hazards are identified, a person has to decide about his or her willingness to be exposed to the identified hazard. When there is a known geological hazard, consideration should be given to buying insurance that will cover the cost of any damage that hazard may cause. The most common type of geological-hazard insurance that is available is earthquake coverage. Plans should be made ahead of time on how to respond in the event of a geological emergency. These plans should include the stocking of food, water and medical supplies and emergency lighting as well as an evacuation plan.


The movement of the land surface from one place to another by water or wind is called erosion. Some of the causes of erosion are farming, mining, construction activities and a wide variety of other activities of man kind. Erosion also is a natural process caused by flooding, the breaking up of cliffs and the washing away of dunes and beaches.

Volcanic Eruption

Some of the most devastating natural disasters have resulted from volcanic eruption. Currently, lava flows in Hawaii are destroying properties as their owners stand by watching helplessly. The eruption of Mount Saint Helens a few years ago damaged properties for miles around. Volcanic eruptions can occur suddenly without warning almost anywhere, but usually they occur in areas known to have a history of volcanic activity. Volcanic eruptions may consist of lava, ash, cinder and mud flows.


Serious life-threatening earthquakes have occurred at least a half dozen times in California during this century (San Francisco in 1906 and 1990, Long Beach in 1933, San Fernando in 1971 and Whittier in 1987). Lesser earthquakes have occurred all over the country.

Earthquake shaking is caused largely by the release of seismic energy during periods of sudden displacement along a fault. A fault is a fracture in the earth where rocks on one side have been displaced with respect to those on the other side. A fault zone is a zone of related faults that commonly are braided or sub-paralleled, but may be branching and divergent. Fault zones of significant width range in length from a few feet to several miles long. A fault trace is the line formed by the intersection of the fault and the earth’s surface. About 70 percent of California land area is in or relatively adjacent to a fault zone.

Fault Creep

Not all fault movement results in violent earthquakes. Fault creep is the gradual displacement of the rocks along a fault line. The forces they create cannot be halted by any means known at this time. A typical fault creeps about half an inch per year. This is enough to substantially damage concrete foundations, street paving, sidewalks, tennis courts, pools, etc.


When an earthquake takes place under the ocean, it can produce a tidal wave also called a tsunami in the parts of the world where this type of wave is common. Some of these waves are very high and have caused tremendous loss of life and damage to property.


The surface of the land may drop away for a variety of reasons. Many of these drops are caused by human activities such as withdrawing ground water for irrigation and drinking purposes or taking gas, oil, coal or other mined ores out of the earth and not replacing it with something else to hold up the ground. Natural causes are hydro compaction and the oxidation of peat.


These are caused when rocks, soil, fill and vegetation work loose from the side of a hill as a result of an earthquake, rain, snow or any other reason, and tumble down the mountain or hillside. Properties on the sides of hills and in the valleys below them also are in some degree of danger. Even an occasional loose rock can cause damage and a major slide can wipe out property and endanger human and animal life. Not all landslides are rapid. Some move only a few inches per year.

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